Your hosting provider who owns the IP sets the PTR record for it. There is nothing to do in the DNS zone editor for your domain.

I have just done it. My hosting provider (digitalocean) automatically created PTR record when I named the host, it just needed to be the full name, ending with the domain. I added the IP in Godaddy's DNS editor. Now nslookup hostname and nslookup IP work just fine.

When I first called Godaddy support they tried to sell me "premium DNS". But unless they own the IP, they could not set the PTR record anyway.